Guiding of threads or filaments



May 15, 1951 s. w. BARKER GUIDING OF THREADS OR FILAMENTS Filed Feb. 21,1947 INVENTOR. 5YnNaY WARREN BARKER treatments.

Patented May 15, 1951 UNITED STATES P GUIDING OF THREADS OR FILAMENTSSydney Warren Barker, Colne, England, assignor to Lustrafil Limited,Nelson, England, a corporation of Great Britain Application February 21,1947, Serial No. 730,000 In Great Britain February 23, 1946 3 Claims. 1

The present invention relates to improvements in devices for guidingthreads or filaments and more specifically to improvements in continuousprocesses for the production and/or treatment of artificial threads.

In such processes it is known to conduct the thread in a series ofhelical loops round a pair of rollers rotating upon shafts Which areinclined to one another, one or both being positively driven. During itstraverse of the pair of rollers the thread may be subjected to varioussuccessive treatments such as setting, washing, drying, bleaching andthe like. The rollers may be cylindrical or may vary in diameter fromsection to section so that the peripheral velocity is accom modated tovariations in the length of the thread as it is extended or contractedby the various In such prior apparatus, the rollers may thus be taperedin one direction or the other at different parts of their length, andthe tapering may be smooth, giving a conical surface, or in stages,giving a stepped surface; but in such known apparatus, the tapering ofthe respectively corresponding parts of both rollers is always effectedin the same way, so that the two rollers are similar.

We have observed that, in the operation of such prior apparatus, atthose places Where the rollers are conical, the diameter of the rollersincreasing as the thread advances, the distance between successive loopsof thread becomes shorter and the loops tend to crowd together.Conversely at those places where the rollers are conical and thediameters decrease, the loops appear at greater distances apart. This.crowding or spreading of the loops leads to difiiculties, for theinclination of the rollers and the tension on the thread (which twofactors determine the distance between successive loops) are selected togive such a distance between loops as is found by experience to resultin smooth working of the process, and any variation from this optimumdistance is usually undesirable.

According to the present invention the crowding and spreading of theloops at conical parts of the rollers may be largely avoided and becomenegligible in effect by employing a pair of dissimilar rollers, one ofwhich is conical or frustoconical whilst in the other roller acorresponding change in diameter is made by a series of steps.

That is to say, the change in diameter of one roller for a given lengthof that roller is exactly the same as the change in diameter for thecorresponding length of the other roller.

In the accompanying drawings, Figs. 1, 2 and 3 illustratediagrammatically several forms of apparatus in which the presentinvention may be embodied.

It is convenient to refer to that surface Tof the step which carries theloop of thread as the tread, and to the more or less perpendicularportion R between one tread and the next as the riser.

The treads are of such depth (1. e. distance between risers) as each toaccommodate a singlev loo or several loops of threadand to permitadvancement or displacement of the thread laterally (i. e. in an axialdirection) to occur freely, within predeterminable limits, along eachtread surface in passing around the roller thus stepped as is clearlyshown in the drawings. In and of itself, tapering certain parts of aroller by thus stepping its surface is not broadly new, of course; for,as already pointed out hereinabove, it has been proposed heretofore thusto taper corresponding parts of both rollers of a cooperating pair, asan alternative to having said parts of both rollers smoothly tapered (i.e. conical), the rollers of the pair being thus alike or similar. But byemploying dissimilar rollers in accordance with the present invention,an entirely novel effect is produced as will now be pointed out ingreater detail.

A normal and satisfactory correction of crowding or spreading of theloops is obtained by making the treads cylindrical and parallel to theshaft or axis of the roller. This is illustrated in Fig. 1, for example,where roller 5 is conical, while roller 0 is composed of coaxialcylindrical portions 7, 8 and Q, which provide the treads upon whichthread It is carried. If a further correction is desired the tread maybe inclined towards the shaft or axis of the roller so that the anglebetween tread and riser is diminished and a dogtooth form is given tothe step, as illustrated in Fig. 2, where roller I I is shown composedof coaxial frusto-conical portions l2, l3 and E4. On the other hand, iffor any reason a correction smaller than normal is desired, the treadmay be inclined away from the shaft or axis so that the angle betweentread and riser is increased. This embodiment of the invention isillustrated in Fig. 3, where roller [5 likewise consists of a series ofcoaxial frusto-conical sections it, I? and IS, the tread inclinationbeing the reverse, however, of that in Fig. 2. The dog-tooth form of theinvention shown in Fig. 2 is useful at the drying stage where thecontraction of the thread as it dries is allowed for by a graduallydiminishing diameter of the rollers. The upper only one of the pair ofcooperating rollers is' accomplished in accordance with the presentinvention are to be sharply distinguished from the V-section grooveswith which it has heretofore been proposed to provide both rollers of acooperating pair in order to prevent lateral 'displacement or roaming ofthe thread in its traverse and to increase its grip on the rollers, bothof which objectives are achieved because the thread lies in the base orvertex of the V and is thus confined and gripped thereby. Since the termsteps is herein employed to provide such sharp distinction, it isaccordingly to be understood as positively excluding such grooves fromwithin its scope.

I claim:

1. Apparatus for the manufacture of artificial threads in. which thethread is conducted in a series of helical loops round a pair ofmutually inclined rotating rollers, at least one of which is positivelydriven, said rollers being tapered for at least a portion of theirlength, corresponding portions of the pair of rollers being dissimilarin longitudinal section in that where one roller changes diametersmoothly over a given length, giving a frusto-conical shape to theroller at that portion of its length, the same change in diameter in thecorresponding portion of equal length of the other roller is made in aseries of steps.

2. Apparatus as claimed in claim 1 in which the treads of the steps arecylindrical and coaxial.

3. Apparatus as claimed in claim 1 in which the treads of the steps arefrusto-conical and concentric with but inclined to the axis of rotationof the roller.

SYDNEY WARREN BARKER.

REFERENCES CITED The'following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date Re. 22,178 O-ppenlaender Sept.15, 1942 1,882,612 Hufford Oct. 11, 1932 2,002,996 Hoefinghoff et al.May 28, 1935 2,020,057 Hartmann et a1 Nov. 5, 1935 2,410,419 Bellezza,Jr Nov. 5, 1946 FOREIGN PATENTS Number Country 7 Date 509,854 GreatBritain July 24, 1939

1. APPARATUS FOR THE MANUFACTURE OF ARTIFICIAL THREADS IN WHICH THETHREAD IS CONDUCTED IN A SERIES OF HELICAL LOOPS ROUND A PAIR OFMUTUALLY INCLINED ROTATING ROLLERS, AT LEAST ONE OF WHICH IS POSITIVELYDRIVEN, SAID ROLLERS BEING TAPERED FOR AT LEAST A PORTION OF THEIRLENGTH, CORRESPONDING PORTIONS OF THE PAIR OF ROLLERS BEING DISSIMILARIN LONGITUDINAL SECTION IN THAT WHERE ONE ROLLER CHANGES DIAMETERSMOOTHLY OVER A GIVEN LENGTH, GIVING A FRUSTO-CONICAL SHAPE TO THEROLLER AT THAT PORTION OF ITS LENGTH, THE SAME CHANGE IN DIAMETER IN THECORRESPONDING PORTION OF EQUAL LENGTH OF THE OTHER ROLLER IS MADE IN ASERIES OF STEPS.